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<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        function getRandom(flag = true){
            if(flag){
                let arr = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f']
                let str = '#'
                for(let i = 0; i <= 6; i++){
                    let random = Math.floor(Math.random() * arr.length)
                    str += arr[random]
                }
                return str

            }else{
                let r = Math.floor(Math.random() * 256)
                let g = Math.floor(Math.random() * 256)
                let b = Math.floor(Math.random() * 256)
                return `rgb(${r},${g},${b})`
            }
        }
        console.log(getRandom(true));
        console.log(getRandom(false));
    </script>
</body>
</html>